Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

[fjhuerta]

Hi all!

I'm building an IDS 25 clone out of 25 Fountek FE-83 drivers.

I wrote another thread regarding what to do with a couple of those little toys, so I decided to go big and build an IDS-25 clone (by Roger Russell).

It has been quite a tiring experience. I'll post pics later, but I guess I have invested close to 20 hours wiring, preparing drivers and making holes on the cabinet, etc. (I didn't build the cabinet, I had it build by someone else). I'm still 2/3rds of the way there before I can finally wire the speakers and start working on the transfer function for the EQ.

I knew this would be a lot of work, but never did I think it'd be so much! It really takes some special dedication.

As it is, the only thing that worries me is - whether the drivers can do real bass. I don't want to use a subwoofer - I want a full-range line array. If I use a sub I'll have tons of integration problems, since the subs will be point sources and the speakers are line-arrays. Everything will sound OK only in one point in my living room.

The thing is, if distortion is too high I won't be able to use the FE-83s that down low... I have this feeling that distortion at 40 or so Hz may be too much and they could be unusable. Something I learned while building the little 3" speaker by Zaph - doesn't matter if the speaker can do 3 mm Xmax if the non-linear distortion profile sucks. :(

Current plan is to use a sharp filter at 30 Hz. I'll start with a UltraCurve based EQ, and then move to a digital MiniDSP unit.

[neildavis]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

I wrote another thread regarding what to do with a couple of those little toys, so I decided to go big and build an IDS-25 clone (by Roger Russell).

Very nice looking cabinets!

It has been quite a tiring experience. I'll post pics later, but I guess I have invested close to 20 hours wiring, preparing drivers and making holes on the cabinet, etc....
I knew this would be a lot of work, but never did I think it'd be so much! It really takes some special dedication.

I can sympathize. I've got a similar project coming up, except it has even more drivers (32 2" drivers plus 48 flat-panel tweeters per side). I'm worried about the amount of time it will take and whether I will live long enough to finish it.

As it is, the only thing that worries me is - whether the drivers can do real bass.

The total Sd of your 25 3" drivers is between a 12" and 15" woofer (700cm^2). However, the Xmax for the FE83 is only 3mm. So the total volume swept by the drivers is on the order of what you can get with a good 10" driver. That's probably plenty of clean output for music, but it's obviously not going to compete with a theater system with a decent sized sub.

[fjhuerta]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Very nice looking cabinets!



I can sympathize. I've got a similar project coming up, except it has even more drivers (32 2" drivers plus 48 flat-panel tweeters per side). I'm worried about the amount of time it will take and whether I will live long enough to finish it.



The total Sd of your 25 3" drivers is between a 12" and 15" woofer (700cm^2). However, the Xmax for the FE83 is only 3mm. So the total volume swept by the drivers is on the order of what you can get with a good 10" driver. That's probably plenty of clean output for music, but it's obviously not going to compete with a theater system with a decent sized sub.

Oh, I don't want big bang explosions, all I'm hoping for is decent output at 30 Hz for music. Roger Russell did it with drivers similar to the ones I'm using, so I guess it's possible. I've had a system with dual 7" woofers and a single 8" in that place - even a pair of RS-125's for bass, and it's OK. Not mind-blowing, but I can't complain. A single 10" may be all I need.

I'm currently using a speaker with dual 10" RS-270s ported at 22 Hz, so I may miss some of the bass, though.

I may start wiring the drivers today. Everything is finally ready. I can't imagine how it'll sound un-eq'd, the drivers by themselves are somewhat bright - so I'll be surprised when there's no treble while listening to the array.

[Jim Griffin]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

If I were you, I would add a pair of active crossover subs to cover 100 Hz and below and call it a day. You will likely have to heavily EQ the arrays and overdrive those small drivers to get close to what you want. Subs are omni-directional so they will match OK with the arrays in your room.

[fjhuerta]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

If I were you, I would add a pair of active crossover subs to cover 100 Hz and below and call it a day. You will likely have to heavily EQ the arrays and overdrive those small drivers to get close to what you want. Subs are omni-directional so they will match OK with the arrays in your room.

Yeah, I know there'll be some important bass eq going on. Although 25 drivers, and the boost a linear array may get me will probably help. From what I've read and modeled there's a natural bass boost for an array like this. If this is true, then eq will not even as heavy.

I'm actually building these praying that Russell's array indeed does work. He says he could get the drivers to 20 hz, and people who have listened to them say bass is impressive. I don't know. Sims don't seem to agree with this, but then again, the only thing I've seen that can somewhat simulate this array is The Edge.

If all else fails, yes, I'll have to build a pair of subs. I don't want to, though...

[Adam_G]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Very ambitious! Love those cabs, hope it all works out for you! I think the efficiency gains and floor-to-ceiling array effects may give you a healthy boost in the bass department, I don't think 20hz is a sure thing, but you should be able to get to 40hz quite comfortably.
I'm enjoying my mini - arrays with 8 of these per side.

[bigfishe]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

I'd take Jim's advice. Shoot for the best mids and highs you can get and let the sub Woffers do the rest.! The man that chose that line array pick those drivers for a reason!

[neildavis]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

I'm actually building these praying that Russell's array indeed does work. He says he could get the drivers to 20 hz, and people who have listened to them say bass is impressive.

I think you will have bass down to 20Hz. With the EQ you are basically adding a Linkwitz Transform, shifting the poles down to a much lower frequency. The question is how much air you can move with low distortion, and whether that is enough. I remember Rick Craig mentioning something about these arrays with EQ being "game changers" for bass, but I think he was using somewhat larger drivers that have more surface area and greater excursion. Of course, a lot will depend on the speaker location, size of the room, and your expectations. My guess is that the high quality midrange and high end will be so satisfying that the bass will be "sufficient". And as Jim noted, a sub should integrate properly if it is needed.

I've always been a fan of driver arrays. Back in high school in the late 60's I modified the door on my walk-in closet to have 24 8" drivers. No EQ, and each driver was just a $2 whizzer-coned cheapie from Radio Shack. But the door was impressive--great mids and a smooth response that was far better than any individual driver. I actually used it through college--and it was a great party speaker. I've always wanted to do some more experimenting with the line arrays, but as you noted, these take time to construct and they are not a simple weekend project.

[fjhuerta]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

I'll know pretty soon what the array does. As of today, it's wired and 10 drivers have been screwed in. EVERYTHING about the array was hard to do. EVERYTHING. If it works then I'll post all about how I did it!

[fjhuerta]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

I'll know pretty soon what the array does. As of today, it's wired and 10 drivers have been screwed in. EVERYTHING about the array was hard to do. EVERYTHING. If it works then I'll post all about how I did it!

My jaw is still on the floor.

Expect a detailed write up....


Omg... I never expected a line array to be this freaking AMAZING.

Ps... This. Is. Bass. Real bass. IB quality bass.

[Adam_G]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

My jaw is still on the floor.

Expect a detailed write up....


Omg... I never expected a line array to be this freaking AMAZING.

Ps... This. Is. Bass. Real bass. IB quality bass.

You're cruel. WE NEED MORE PICTURES.

[Tin_Ears]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

You're cruel. WE NEED MORE PICTURES.

Agreed... this is like a burlesque show with no nude ladies.:(

[neildavis]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Omg... I never expected a line array to be this freaking AMAZING.

Ps... This. Is. Bass. Real bass. IB quality bass.

So do you think it will work OK with 36 2" drivers? :D

I'm laying out a 20-channel amp for my line array with 3 ADAU1701 chips to provide EQ and delay. The goal is to be able to change the effective curvature from concave to convex, with power tapering (16 woofer cells and 24 tweeter cells). But as Bob pointed out, this may end up being a bucket list item that survives me :o.

[Tin_Ears]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Neil... please tell us you're not ill. We need you here. If you're just a whiny old coot like me that's okay but please don't die until we've completely robbed your brain of every last candlepower of brilliance.

[neildavis]

Re: Yet Another IDS-25 Clone! 25 Fountek FE-83 drivers in a line array

Neil... please tell us you're not ill.

I'm fine--just being facetious. But it's a big project, with lots of electronics, lots of software, lots of testing, lots of wiring, and lots of drilling, cutting and finishing. I like doing big projects, but as the OP pointed out, the line array projects are especially tedious and sometimes you feel like it will never get done. I've been working on laying out the amplifier circuit board for a long time now, and it's still only about 75% done.

This project is especially slow because I've had to make a couple of prototypes to prove some new concepts. For example, one of the problems I had to address was how to send data to both speakers at the same time to update the DSP settings. There are twenty channels of class D amplification, so the DSP and amps needed to be located at the speaker to keep the connections simple and to keep RFI to a reasonable level. I didn't want to use a separate control bus, so I had to figure out the code to use the user bits in the SPDIF data frame to send commands to the DSP. But I finally got that working, so now I can send "curvature" and volume and filter commands to both speakers through the SPDIF connection. Just lots of challenges like that along the way...

But of course the biggest challenge was getting my wife to believe that this speaker would sound good yet be unobtrusive in our dining room area, and that I really needed to spend all of this time on it :o. I'm sure the OP had the same problem...